Course Content
Introduction to SQL
1. Retrieving Data
Retrieving Individual ColumnsRetrieving Multiple Columns Retrieving All ColumnsRetrieving Distinct RowsLimiting ResultsChallenge: Find the Population of the CountriesChallenge: Find All CountriesChallenge: Find All Countries With Their IDsChallenge: Find Country CapitalsChallenge: Find the Regions in Which All Countries Are Located
2. Sorting Retrieved Data
Sorting DataChallengeSorting by Multiple ColumnsChallengeSpecifying Sort DirectionChallenge: Sort the Countries by Region and CapitalChallenge: Sort Capitals in Descending OrderChallenge: Sort Countries in Ascending OrderChallenge: Find Countries, Their IDs, and Their PopulationsChallenge: Find Countries, IDs, Populations, Regions, and Sort ThemChallenge: Find All Continents and Sort Them in Ascending Order
4. Advanced Data Filtering
Introduction to SQL
Sorting by Multiple Columns
We can also sort by multiple columns. We need to specify the column names separated by commas. Let’s look at the example that retrieves three columns and sorts the results by two of them: first by population
and then by capital
.
Task
Retrieve four columns using the SELECT
statement, namely: continent
, region
, population
, and capital
(please retrieve these columns in this order). Then, sort the result by two of them: first by continent
, then by population
.
Here's a short example of the country
table:
id | name | continent | region | surfacearea | capital | population |
1 | Japan | Asia | Eastern Asia | 377829 | Tokyo | 126714000 |
2 | Latvia | Europe | NULL | 64589 | Riga | 2424200 |
3 | Mexico | North America | Central America | 1958201 | Mexico City | 98881000 |
... | ... | ... | ... | ... | ... | ... |
15 | Malta | Europe | Southern Europe | 316 | Valletta | 380200 |
Everything was clear?
Section 2. Chapter 3